Income Taxes - Income Tax Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Current income tax expense (benefit)	$ (33,614)	$ 14,480	$ 20,328	$ 43,984
Deferred income tax expense (benefit)	43,130	(950)	(8,803)	(1,625)
Income tax expense, as reported	$ 9,516	$ 13,530	$ 11,525	$ 42,359
Effective tax rate	9.10%	10.80%	4.50%	11.10%